The invention relates to a three-phase synchronous machine having a rotor with permanent magnets and an induction cage.
Synchronous machines, particularly with permanent magnet excitation, are used for example as so-called servo drives in production machines, preferably machine tools. In order to increase the productivity in this case, it is necessary to keep not only the machining times but also so-called secondary times of the machine tools as short as possible. During the secondary times, drives are accelerated and are operated in rapid traverse. This phase requires the drives to have an acceleration capability for a short time. The acceleration capability depends on the masses to be accelerated and on the torque emitted from the respective drive. Particularly in the case of direct drives, the torques are of major importance, since there is no torque conversion via a gearbox.